Berkeley 59 is an open cluster of stars located in the constellation Cepheus at an approximate distance of 3,000 light years from the Earth. Berkeley 59, is the primary source of ionizing radiation illuminating the star forming nebula designated Sharpless 171. The cluster is only a few million years old. The bright star, located in the upper center-right, is one of the hottest stars within a thousand parsecs of the Sun. It is an eclipsing binary containing an O5V star (BD+66 1673) with a surface temperature of almost 45,000 Kelvin. It has luminosity approximately 100 thousand times that of our Sun.